Sep 5-10, petaloid; pet and staminodes none; pistils several, usually 8-12; achenes fusiform, saliently several-ribbed, tipped with the persistent, sessile, capitate stigma; perennial, glabrous herb from a small cluster of fusiform tubers, bearing a few long-petioled, 2-3-ternately compound basal lvs, an erect stem, and a few-fld umbel subtended by 2 or 3 virtually opposite or whorled, sessile, ternately compound involucral lvs. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
